


The Mysterious Fathoms Below

by Inarchem



Category: Kingdom Hearts
Genre: Alternate Universe - Merpeople, M/M, Rating for Lea Discovering Human Anatomy and a Depiction of Near-Drowning
Language: English
Status: Completed
Published: 2020-12-23
Updated: 2020-12-23
Packaged: 2021-03-10 16:54:03
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 9,327
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28120446
Author URL: https://archiveofourown.org/users/Inarchem/pseuds/Inarchem
Summary: Isa always believed that the idea of mermen belonged solely to superstitious sailors and drunkards. However, one day, Isa is saved by one such creature when he is thrown overboard by a crew of pirates. But that is not the end of his troubles. This particular flame-haired merman is determined to convince Isa that he is a lover that has been returned to him by the hands of fate. And despite his skepticism, Isa will soon find that the water holds memories deeper than the darkest depths of the sea.
Relationships: Axel/Saïx (Kingdom Hearts), Isa/Lea (Kingdom Hearts)
Comments: 13
Kudos: 37
Collections: MoonFire Big Bang 2020





	The Mysterious Fathoms Below

**Author's Note:**

> For the 2020 MoonFire Big Bang!
> 
> This was a collaboration with the incredible artists [Michy](https://twitter.com/_yumiluna/status/1341894423542566919) and [Lico](https://twitter.com/LicoriceRoll/status/1341849616342523905)!
> 
> Thank you to [Liv](https://twitter.com/bookworm_lyv) for being a wonderful beta!

> _I'll tell you a tale of the bottomless blue,  
>  And it's hey to the starboard, heave-ho,  
> Look out lad a mermaid be waiting for you  
> In mysterious fathoms below_

Isa had felt a strange sense recently, as he led his ship and crew into the ocean. While before he merely held a sailor’s healthy respect for the sea, now the waves moved and churned with something that seemed… darker. More alluring, almost. He found himself forcibly reminded of old, drunken sailors, rambling about the sea calling their name, as they told nonsensical tales of their encounters with mer-people and other such nonsense. Isa knew better than that. He knew that there were no voices in the waves, and he knew that merfolk were simply tales sung by superstitious sailors. 

It was all laughably ridiculous. 

Still… on some nights, when he perched his elbows on the ship’s railing and quietly listened to the dull roar of the waves, there seemed to be something out there. Calling to him. 

But those quiet nights abruptly came to an end when his ship was attacked. 

Isa’s crew, well-manned and strong, fell quickly to the bullets and blades of bloodthirsty pirates. And with a practiced ease, the pirates had made sure to loot every spare inch for any possible valuables before setting it ablaze. The mast had given an almighty groan as it splintered at the fire, then cracked and fell as flames licked up the wood. All of that was followed by a mighty _boom_ that could be felt even from the pirates’ ship, where Isa and the others were held captive, as the flames finally reached the stores of gunpowder. 

It would look like an accident, Isa thought as he struggled against his bonds, even as a wound sustained earlier during the fight continued to bleed through his shirt. An accident to all those except who were there. And judging by the toothy, grinning faces of the crew surrounding them, Isa would venture to guess that the pirates planned to shorten that list considerably. 

“Did you find it?” A low, sonorous voice intoned near the helm. Isa’s eyes snapped up, and he saw a finely dressed man in a long black coat, embellished with silver filigree about the trim. Most likely the ship’s captain, given his fine dress and air of authority. 

“No sir,” an eye-patched pirate replied, his jagged scars on his face stretching horrifyingly as his lips twisted into a shark's smile. “But we got something better.” Quick as a sea serpent, his arm darted out and dragged out a captive by his slate-colored hair. Tossing him onto the deck, Isa saw two other burly captives stiffen and strain against their ropes, obviously trying to break free and reach the lad. “The old man’s favored apprentice himself. Say hi to the captain, Ienzo.”

Ienzo gave a wince, pushing himself up to his knees, before shooting an irritated look to the first mate. “You’re wasting your time here. What you’re looking for is beyond your reach.”

A gun cocked, and the cold barrel was suddenly pressed against Ienzo’s head. “Now, that wasn’t very helpful. Want to try again? Or would you prefer to try your luck with the sharks? I think a morsel like you would last—” 

“That’s enough,” Isa barked out. Immediately, the captain and first mate’s eyes were transfixed on him. Baring his teeth in a growl, Isa met their gazes head-on. “I said, that’s _enough_.” Silence rang through the ship for a moment, as the captain tilted his head and steadily ran his eyes across Isa. He tried to meet that gaze, but the emptiness within those eyes sent a shiver down Isa's spine. With an imperceptible sigh, the captain shook his head. 

“Discard the extra baggage, Xigbar.”

“Hey, whatever you say, boss.”

The captain turned back to his cabin, and as he vanished into the gloom beyond the torchlight, the remaining pirates circled around the captives with a terrifying glee. 

Xigbar now stared down at Isa with an eye that glinted gold in the night’s cold light. “Now gents,” he purred, “The ocean is hungry tonight, and I think she would appreciate this morsel. Let’s show her how generous we can be.” Without warning, Isa found himself suddenly pinned down to the deck by multiple sets of hands as netting was wound around his ankles, binding his legs together. At one point, he watched as a cannonball was tied within the nets. Beginning to realize the fate that was in store for him, Isa began to thrash against the men’s hold, but his struggling was useless as they dragged him to the deck’s railing, where the first mate waited. 

“No hard feelings,” Xigbar smirked as the pirates sat Isa on the railing. “Just following orders, you understand. But hey, look on the bright side! Maybe you’ll drown before the sharks can sniff out the blood from that gaping wound of yours.” Isa’s eyes blazed in fury, but the pirate only responded with a roguish wink. "Pleasure seeing you again, but off you go,” he said with a rough shove, forcing Isa off the railing. There was a moment of silence as the wind whistled in Isa’s ears— but only a moment. Then he crashed into the black, choppy waters of the ocean. 

He tried to stay calm— to recall the way he had painstakingly trained his body to reject panic. But as the water closed over his head, Isa could only feel the weights dragging him farther down, down, down. Fire burned down his throat, through his nose, to his lungs. The taste of salt overwhelmed his tongue, drying it even as water flooded the roof of his mouth. 

A high pitch rang in his ears, as the waters’ crushing pressure surrounded him. Not even the harsh moonlight from above could pierce this darkness, leaving Isa to sink in a black hell. His lungs burned in their demand for air, and Isa was left to wonder how precious few seconds he had left before he was lost to the waters. 

But distantly, beyond the sensations of his death throes, Isa became aware of something else. An odd echo that emerged through the dark depths of the wine dark sea— lonely yet strong. It rose and fell through the waters, like a wordless melody. And even as Isa struggled to retain consciousness, he found himself enraptured by the strange song. 

There were tales of such encounters, shared in daring whispers among members of superstitious crew members. Tales of beautiful men and women that possessed the upper torso of a human, but the gleaming tail of a ravenous fish. Isa had always scorned those tales for being merely that— tales. But as the eerie song drew even closer, ringing in his head like church bells, Isa found that it was becoming harder to dismiss those fears that suddenly seemed much more possible. 

Suddenly, the waters shifted behind him, as if there was a great presence languorously examining him from the darkness. And as he twisted in his bonds, Isa glimpsed several pinpricks of phosphorous green light, undulating and illuminating the shadow of something _huge._

A monster of the deep, Isa thought, his stomach sinking. Perhaps considering him as a meal. The creature was easily the size of a man, from what he could glimpse from the light of the creature's elongated bioluminescent spines. But Isa’s vision soon began to blur, as his lungs threatened to collapse, and the space in front of him turned into a smeared whorl of black, green, and… red? 

Suddenly, Isa felt the impossible sensation of two clawed hands holding his face, gently cupping his cheeks. He struggled to focus his eyes— to face his death to the very end. But all he could see through the gloom was a pair of glowing, green eyes— fierce yet tender. _Human._

The hands were strong, despite their slim build, and they kept him from descending deeper into the abyss. Somehow this position felt… familiar. The merman pulled him closer with that inexorable strength. But that couldn’t compare to the surprise he felt when suddenly the merman’s thin lips pressed against his own. 

The sound of surprise he gave was swallowed up by the water and by the merman, as the last of his precious air floated away as bubbles. But with the darkness finally beginning to claim him, the last thing Isa saw was a strangely worried expression crossing those entrancing, green eyes. And in the final moments of consciousness, he thought he could hear a voice singing his name.

#### * * * * *

Isa slowly awoke to the feeling of several hard stones jutting uncomfortably into his back. His mouth was dry, as if he had been sleeping for hours, and his legs _ached._ But more than that, he could hear the notes of a song, floating and echoing around him. There were no words— only long, drawn-out sounds that were gently keened out. He could feel the sensation of fingers gently carding through his hair— and although they felt strange and unfamiliar, clawed and webbed, there could be no denying the care and tenderness inherent with each stroke. 

When was the last time he had been touched like this? Like he was something infinitely precious and delicate.

The wordless song contained a gentle melody, much like a lullaby. But there was something inherently… sorrowful contained within each note. The melody rose and dipped like the tides, but it also fiercely reminded Isa of how a man’s shoulders could quake as sobs wracked his body. There was unspeakable sorrow there, but also a hope obscured deep within that sorrow. And as the notes of hope became more profound, he felt the clawed fingers gently trace a pattern on his cheek. Unconsciously, Isa turned his face towards that cool touch, as if some part of him yearned to comfort the source of this song. 

Green is the first thing that he sees as his eyes blink open. Green as bright as the sun’s flash before its descent below the horizon. As his vision became less blurry, Isa found himself staring at a pair of startling green eyes. Now he could see that they were surrounded by inky blank sclera that peered at him in return. Wild hair that was the fiercest red he had ever seen surrounded the stranger’s face in a wild mane, where the sea salt had solidified a few strands into wavy spikes. However, Isa’s eyes were instantly drawn to the gaping maw of sharp fangs— the current source for the anguished song that echoed around them. 

“This sounds so familiar,” he said before he could stop himself. The song drew to a close, and the stranger gave a slow blink.

“Because you’ve heard it before,” the merman easily replied, looking at Isa with an expression that was nearly as tender as his song had been. “But then, you also composed it.”

Isa’s brows furrowed, and he sat up from the flat stone where his head had rested. From the corner of his eye, he saw the merman’s claws twitch towards him before stopping— as if holding himself back. “That’s impossible. I’ve never written a song in my life.”

“You have,” the merman asserted, his tone unchanging in its care. “But not as you are now.”

Isa scoffed, moving to sit up, but he let out a sharp hiss as the quick motion irritated the wound in his side. The merman sat up straighter, the water of the shallow pool rippling in response. “You’re still hurt,” he objected, “You need to stay still until your wound can heal.” 

“Who are you?” Isa bit out instead, as he braced an arm behind him, his other arm cradling his side. “And why have you brought me here?”

‘Here,' being a large cavern that contained a narrow shelf of rocky land that was just large enough for a man to rest on. The greatest portion of the cavern was taken up by a pool where the merman was presently sitting, the flukes of his tail drifting gently in the water. 

The cavern could have been just as dark as the depth Isa had been saved from, but the waters were alight with some sort of algae that gathered most densely around the waves that tickled Isa’s feet. Looking around in wonder, Isa could see great stalactites and stalagmites that reflected the flow of the water, like a glass mirror. But Isa’s eyes were drawn away from the glittering cavern, as the merman before him propped himself up on his arms, pulling himself closer onto the shore. 

“My name is Lea,” the merman responded, looking intently at Isa, as if searching his eyes for some kind of reaction. “And I brought you here, because you are my mate.”

A beat of silence.

“I beg your pardon?” Isa said, barely keeping the disbelief out of his tone. 

“You're my mate,” Lea repeated, as if it was the simplest thing in the world. “I lost you, but now the sea brought you back to me. But Isa?” the merman said, suddenly taking on a much more casual tone, as his tongue clicked against his fangs. “You have a knack of getting into trouble.”

Isa found himself speechless at that— not knowing quite which aspect to address first. 

“Lucky for you and your scale-less self,” Lea said, his red spines dipping in the water as he crawled forward by his arms, “your wound is manageable. I just need to—"

Isa tensed and drew back, his bare feet skittering on the rocky shore. “Keep your distance!” He hissed, “Why should I trust you?”

Lea examined Isa closely, his clawed hand still held out in that half-aborted offer of assistance. Glowing green eyes narrowed, and Lea’s spines bristled on his back and elbows. Glancing at them, Isa couldn’t help but note the sharp edges of those spines and recall stories of brightly colored fish whose venom could stop a strong man’s heart. 

“No reason?” the merman replied, green eyes glowing even brighter in the cavern’s dim light. “Well, how about this. If I had wanted to, you would have been drowned and in the belly of something worse than me by now, wouldn’t you?”

Isa paused, as the truth of the situation impacted him. Lea scoffed, tail lashing in the water. “That’s what I thought.”

“... My apologies,” Isa murmured, down casting his eyes. 

Lea huffed, but his eyes gentled, just a touch. “Well ‘sorry’ don’t always cut it! But I guess I could make an exception since you’ve had a near-death experience. I’ll tell you what,” he said, the frustration quickly melting away into a devious grin. He approached again, slower this time, as he gauged Isa's reaction. Conceding to Lea's logic, Isa reluctantly nodded, allowing him to come closer. Lea's tail curled in satisfaction. “You can make it up to me.”

Isa swallowed, eyeing those fangs— but less so out of fear. “And how’s that?”

Abruptly, he felt Lea’s tail wind around his ankle and yank it out from under him, sending Isa flat on his back with a short shout. Before he could sit up, Lea’s hand landed on his chest, keeping him on his back. Oddly enough, Isa noticed, Lea’s hand was glowing the same color as Lea’s eyes. “By _holding still,_ and letting me do my job!” Lea growled out. 

Lea’s hand shifted over Isa’s side, alighting itself tenderly over the wound there. He didn’t waver, even as Isa hissed in pain, and the pinched furrow between Lea’s eyebrows grew deeper in concentration. Slowly, Isa could feel a warmth emanating from the spot, relaxing his muscles. And when Lea eventually drew his hand away, Isa found that his wound had vanished entirely—not even leaving a scar behind. 

“How did you…?” Isa murmured, perplexed. 

Lea gave an ungracious snort at that. “Magic, of course. What? Did you think that living under the sea gave you no perks at all?”

Isa flushed, unable to quip back at that. Lea’s expression softened. “Oh gods below, you really had no idea, did you? … You’ve forgotten so much, Isa.”

Hearing his name on the merman’s tongue was a strange experience, pleasantly prickling the fine hairs on the back of Isa’s neck. And yet… something about it didn’t seem quite right. As if it wasn’t meant to be said so sadly by this man. 

But before Isa could question it, the merman sat up, green eyes flickering towards the water reluctantly. 

“You can’t stay here much longer,” Lea said, although he spoke as if the words had to be ripped from his lips. “The air is dead here, and if you stay for too long…” 

The unspoken implication rang through the air. “Otherwise, I would keep you here for myself,” Lea said with a smile that was all-fangs. “Unfortunately, human lungs need fresh air, so… not as ideal as I would have wanted. But I guess it works out in your favor.”

There was a brief pause, where only the slow beat of waves on the stony shore could be heard. 

“What do you advise?” Isa asked, steeling himself for whatever answer may come. 

Lea looked surprised yet pleased that Isa was willing to hear him, and he didn’t waste time before explaining. “I can lend you some of my magic again,” he answered easily. “That should be enough to help you get to the surface. But don’t worry,” he said, giving a toothy grin, “I’ll be nearby. You won’t have to worry about going through that journey alone.”

Isa huffed, fixing the merman with a skeptical look. “I am not _worried._ I’m sure I can handle a swim just fine. But… what do you mean ‘lending your magic?'” I don’t recall you doing anything like that earlier.”

“Yeah, your human body had been through a lot at that point. I don’t really blame you for not remembering.”

Isa fought to roll his eyes again at the words ‘human body’. As if the merman considered it some kind of detriment. 

Seeing the confusion on his face, Lea elaborated, “I’ll transfer magic from my center to yours. It usually requires some contact.”

Contact…? What did he mean by…

Suddenly, Isa recalled the sensation of cool, thin lips pressed firmly against his own.

Oh. _Oh._

Feeling a heat crawl over his cheeks and down the sides of his neck, Isa cleared his throat and faced the merman with as much dignity as he could. “‘Contact.’ Understood.”

Lea nodded, but squinted his eyes in fondness as he caught sight of that delightful flush. “Didn’t embarrass you, did I?” he smirked.

Isa’s brow twitched, and he fought off the urge to splash out at the merman. “Not at all.” 

“‘Not at all,’” the merman repeated with a slight drawl, even as those green eyes glittered in mirth. “Good to know. Would’ve hated to get you all hot and bothered. Humans are so delicate that you might have overheated and died.” Despite the coy tone of his voice, Lea’s tail gave his amusement away, as it splashed in the shallow rocky pool. 

Despite himself, Isa found his lips quirking up in response. “Delicate? At least I wouldn’t be a dried-out fish on the beach.”

Lea seemed to wince at those words, Isa noticed. An awkward silence passed between them, before Isa curiously looked towards Lea.

“... Why are you doing this?”

Lea’s expression softened at that question, but there was a sad look that entered his eyes. “Like I said, because you are my mate. You may not remember our promise, but I do. And I’m never leaving your side again… even if you no longer want to return home. Got it memorized? Now… let’s get you back on land.”

Holding out his hand, Lea gently guided Isa into the water. Stepping carefully, he felt the water pool around his waist. “Careful now,” Lea said, his eyes examining Isa’s legs closely. 

“I’m not going to break,” Isa huffed as he began to tread water. 

Lea said nothing at that— only loosely wrapped his tail around Isa. “Humor me,” he murmured, green eyes going soft. And as Isa felt those clawed hands cup his cheek once more, he found himself tilting his chin up, trusting Lea’s tail to hold his weight. And as his eyes slipped closed, he felt familiar lips settle over his own, a pleasant shiver running over his shoulders. 

When not fearing death of drowning, this kiss was much more pleasant, Isa found. Lea’s lips were smooth, and reminded him of a breeze, rippling the waters of the ocean in its wake. 

All too soon, Isa felt Lea pull away. “C’mon,” Lea said, “That should be enough.” Taking Isa’s hand, Lea pulled him deeper into the pool, until both of them were drawn under, leaving the cavern behind. 

Isa felt anxiety bubbling within him as the water closed over his head. But as he took a tentative breath, he found that the water wasn’t filling his lungs and drowning him as he feared. Instead, he almost seemed to be breathing normally? 

The merman’s grip tightened around him slightly, and as he looked at him, there was satisfaction reflected in those green eyes. But also a sense of humor, as the merman quirked an eyebrow as if saying, _‘See?’_

Biting down a smile of relief, Isa released his hand and began swimming ahead of Lea, eager to explore as much as he could with this newfound gift. 

Lea watched with pride as his mate took to the water, navigating their old territory like a natural. Which he was, he reflected. Even if Isa did not remember their past lives, or their shared connection, he was still the same man that Lea had sworn himself to. 

He could still remember the bleak day that Isa had died. Roxas and Xion had still been guppies at the time, and thankfully could not remember the worst of the disaster. So Lea had borne it himself. 

The two children had played too close to the boats. He and Isa had only turned away for a moment, but that had been enough for them to hear a sharp shriek of fright. Roxas had gotten trapped in the nets of a nearby fisherman, and was rapidly being pulled up with the rest of the catch. Isa had swam over in a flash of blue-silver scales, and cut Roxas out of the net with his claws alone, the instant before the net was heaved above water. 

But there had been a cruel trick within those nets, and rather than swimming away to rejoin his relieved family, a knot had tightened and caught Isa’s tail in the netting.

No amount of thrashing could set him free, and as Lea had watched as a dozen more nets were thrown into the water to ensnare his mate, he had known that to help Isa now would mean risking their entire family. 

Isa had known that too. In those last, fleeting moments, there had been resigned acceptance in Isa’s eyes, even as he fought for escape. 

Lea would never forget the sight of his mate, caught in the net and dragged ashore. He had watched from afar, hidden behind a cropping of sharp rocks. He had heard the humans call his beautiful, radiant mate ‘too wild to keep alive.’ And he had watched as Isa gasped his last rattling breath on the dry, blistering sand, far from the home he loved. 

It was too dangerous for Lea to even offer the sending song for his mate’s spirit to return to the sea foam, and he was forced to watch as Isa’s tail gave a final, limp slap upon the beach, before his eyes went as pale and glazed as sea glass. His claws had barely stopped twitching before the humans descended upon him, poking him and tearing out his scales, already loudly inquiring to each other what kind of price they could fetch. And while Lea watched them, his sorrow quickly coalesced into a seething hatred.

He had not been able to save his mate. But he had devoted himself to the slow death and devouring of each fisherman that had been present that day. He spent years uncovering dangerous spells once thought lost to his people, and in learning them, Lea rose in power. Perhaps if he had these spells before, he could have saved Isa. But for now, he would sate himself on revenge and protecting Roxas and Xion.

There was only one left— the traitor with the covered eye. But while Lea had hunted him, he had instead found himself unexpectedly and elatedly reunited with Isa once again— but in the form of a human.

This revelation presented no challenge to Lea. As he continued to watch his regained mate swim through the ocean with four clumsy limbs, Lea swore that he would never fail him like that again. 

Ignorant to Lea's thoughts, Isa looked back and smiled at him. The merman’s magic had given him clearer sight than his human eyes would have allowed. And maybe it was Lea’s presence, but even the more dangerous fish gave them a wide berth, allowing Isa to explore the sea with a newfound wonder. 

Feeling a smooth, webbed hand slide against his own, Isa looked in confusion as Lea swam up beside him. The merman only offered a wink, before gently tugging Isa along by the hand. 

Daylight streamed through the water, transforming the gloom that had once tried to drown Isa into glittering shades of blue and green. Following after Lea, Isa could see a great coral reef spanning out before them, with all manner of fish swimming around them. 

Unfortunately, all too soon, Lea began to pull Isa upwards by his hand, swimming towards the surface. As both their heads broke the water’s surface, Isa could see the familiar port of his island in the near distance. 

“You can swim from here, right?” Lea asked. “I can’t go much farther without attracting attention.”

Isa nodded, relieved to nearly be home… but also feeling a strange twinge of regret in his heart. “What about you?”

“What about me?” Lea smirked.

“Will I… see you again?”

“Aw, missing me already? I haven’t even had the chance to leave!” Lea teased, green eyes glittering. But when Isa continued to stare at him, the smile slowly slid from his face in favor of a more serious, genuine expression. “One day, you might. Some things need to be taken care of before that can happen. But Isa?” Lea said, cupping his cheek. “I made a promise to you once. And now I’ll make another one: I’ll come back for you. Understand?”

Isa slowly nodded. A sad smile twisted his lips. “I’ll get it memorized.”

Lea returned the smile, gently bumping their foreheads together. “Good.” He took a deep sigh, closing his eyes. “Good…”

For a few moments, they simply remained in the water like that, neither one willing to move away just yet. It was only when a seagull cawed directly over their heads that Isa was forcibly snapped out of the reverie. Lea was intently staring at him, as if trying to memorize every minute detail of this moment. 

“Go on,” he said, fangs and salt making his voice rocky. “Go home.” Before Isa could reply, Lea abruptly vanished back under the water, his tail catching the sun’s light in a dazzling display of crimson, before vanishing completely back underwater. 

A few fishermen in the distance gave low sounds in response to the loud splash, before catching sight of the lone man floating in the water. 

Boats already beginning to dart towards him, Isa forced himself to tear his eyes away from the rippling waters. 

Lea had promised to find him again. But who was to say how long that would take?

#### * * * * *

The next day found Isa waking up in his own bed well before dawn. Sleep had eluded him that night, with promises and haunting melodies whispering in his ear. Despite his best ability to dismiss his entire encounter with Lea as a dream, Isa found himself unable to forget the merman that had saved him.

Deciding that there was no use in wasting anymore time, Isa rose and began to dress himself. Isa’s station as captain didn’t lend him a particularly deep coinpurse, but it had been enough to buy a small house far from the rest of the town, with a courtyard that transitioned into a natural lagoon. It was a calm area, which gave Isa the solitude and respite he needed. He had always felt a sense of peace when he came here. While he had never questioned it before, his encounter with Lea left him wondering if there was more to it, than a simple change of pleasant scenery.

He found himself wandering the lagoon now, watching as the sun began to rise over the ocean’s horizon. And as he watched the dawn in silence, his thoughts unconsciously began to turn to the merman from the previous day. Isa had never told Lea how to find him, he realized with a twinge of disappointment. The sea brought a new sense of longing to Isa, stronger than in the past. And Isa was at a loss at how to cope with these feelings alone. He had never been aware of this loneliness before— but meeting Lea had triggered an awareness of it. Now Isa wasn't sure how to move on from this point. It was as if years of mourning had suddenly caught up with him. 

Without someone standing at the empty space at his side, the entire world suddenly felt emptier for it. Frustrated with his own melancholy, Isa scoffed, turning back towards his house.

But before Isa could turn his back, a sudden splash caught his ear. Turning around, he saw a strange figure in the distance. Squinting his eyes against the dawn’s light, he watched as the figure came closer and closer to the sandy beach of his lagoon. Strange… the closer that the figure swam, the more it looked like someone being supported by two others in the water? But that was impossible. The lagoon led to the open ocean. If someone was to swim towards his house, they would have to come from—

“Isa!” 

Suddenly, Isa found himself bowled over by a tall, lean figure. The air knocked out of him as his back hit the sand, Isa dazedly looked up, only to see an incredibly familiar face smiling down at him.

“Lea?!” 

“The one and only,” he preened as the early sunlight caught the red of his hair. “I told ya I’d be back, remember?”

“I mean, yes, but I— I didn’t expect you to come back so soon!” 

“I’m expedient when I want to be, even though it takes a while to make a spell for human legs,” Lea preened, as if expecting Isa's praise. But instead, Isa found himself shaking his head in disbelief, even as a smile crept towards his lips. This merman was something beyond impossible… 

Wait. Legs? 

Lea adjusted himself on top of Isa, and the man came to an abrupt realization. 

“Lea! You have legs!” he sputtered.

“Uh, yeah,” Lea said, nonplussed as he stretched his arms around Isa’s neck. “Unless I got it wrong?” He looked down between them, as if making sure. 

That successfully rendered Isa incapable of thought for a brief moment. Isa was only taken out of his stunned silence as a shell sailed through the air, knocking against Lea’s head. 

“Stop being embarrassing already!” a boy’s voice sounded nearby. Peering over Lea’s shoulder (and struggling to not let his gaze wander further south), Isa saw the heads of two teenagers poking out of the water. One was a blond boy, while the other was a girl with short, black hair. Both figures seemed… oddly familiar.

With an off-handed gesture, Lea swirled his hand and made a small wave crash over the blond’s head. Offering an awkward wave as the teen squawked in indignation, Isa put his hands on Lea’s shoulders and helped the man stand up. Well, mostly. Lea’s knees were still a little wobbly, which led to him leaning heavily against Isa. Which was no matter, as Isa felt more secure with his arm draped around Lea’s shoulders. But when he looked back towards the open waters, the two figures had disappeared. 

“Roxas and Xion,” Lea helpfully supplied, “They… wanted to see you. But I couldn’t make enough of the potion for all three of us to come on land.”

Hearing the wistful note in Lea’s tone, Isa gave his hip a small squeeze in a gesture that felt surprisingly familiar, despite its intimacy. Lea was doubtlessly shocked at his forward nature as well, if the surprised noise he made was any indication. 

“Well, you’re already here,” Isa said, raising a brow in amusement. “I might as well give you a tour. But first… we’re going to need to find some clothes for you.”

Granted, Isa hadn’t known how much Lea would hate wearing pants. But if he wanted to wander around town, there was no helping it. But the merman-turned-human was going to let Isa know how displeased he was, if the way he pouted and crossed his arms in the carriage-cab was any indication. Regardless, it _was_ rather cute how he pretended to be disinterested, when his eyes kept darting out the window in curiosity. 

“So let me get this straight,” he said, “You humans have perfectly functioning legs that can get you from place-to-place. But then, rather than use them, you have other animals tug you around?”

“Surely you have something like that in the… country you’re from,” Isa said, mindful of the cab driver. “It can’t be that much of a shock.”

Lea scoffed but offered Isa a smile. “Fair enough. Where are we going anyway?”

Isa quirked his lips. “Somewhere better than a cavern, I’ll tell you that.”

“Low blow, Isa.”

He hummed noncommittally, nonetheless pleased that he could at least stump Lea momentarily. Soon, the cab came to a stop. Exiting first, Isa held out a hand to help Lea out of the carriage. “I was thinking I could show you the gardens first, but we’ll have to do some walking to get there.”

“Yeah, walking,” Lea said, “One of my natural-born talents. Lead the way then. Let’s see what all the fuss is about.”

Chuckling, Isa offered Lea his arm, who just looked at it in confusion until Isa linked their arms together. It was pleasant to hold Lea close like this; however, as he guided Lea into town, he missed the smug, pleased look the man wore at their proximity. 

It was Isa’s intention to make a quick trip within the town, not sensing that Lea held particularly fond feelings towards humans. But to his surprise, Isa found himself being regularly yanked back as Lea found some new stall to gawk charmingly over. Between the glassblower, jeweler, musicians, and tailors, Lea’s eyes would most likely be stuck in a permanent glaze of fascination after this day. A part of Isa was glad he could share this experience with Lea— exchanging the small wonders of his own home with the ones that Lea had shown him. 

“Do you not have objects like this under the sea?” Isa asked, as Lea pocketed a small glass charm that Isa purchased for him. 

“I don’t know what you’ve been taught, but human trinkets don’t particularly flourish in water,” Lea snorted, “Fabrics are eroded, and jewels rust away. So this… is the first time I’ve seen it so new. Everything is more beautiful than I thought it would be.” 

Isa looked over and saw that Lea was resting his eyes on him. A flush crawled over his cheeks, and he cleared his throat. “Come, we’re almost there.” 

It had taken them nearly the entire day, but they finally reached their destination. As sunlight poured around them, Isa showed Lea a set of gardens open to the public. “We don’t have reefs on land,” he smiled, “But this could be a close comparison.”

Drawing Lea through the rows of rose bushes, full of riotous colors, and hanging vines of wisteria, Isa never once let go of Lea’s hand. He wanted to show him every bloom, every form of beauty that could be found in his world. And while Isa wasn’t entirely sure of the reason why, he found that he couldn’t care— so long as Lea’s fingers were laced with his own. It was only when they both found a small table by an outdoor cafe that the two finally sat down, exerted but smiling. 

Finally in a moment of stillness, Isa took in the sight of Lea in the sunlight. With the salt once crusting it now gone, Lea’s hair rose in half-spikes that waved slightly in the warm, summer breeze. He was a handsome man, Isa realized. 

“What are you thinking?” Lea asked, reaching to cup Isa’s cheek. 

Isa smiled, reaching to hold Lea’s hand there. Offhandedly, he caught himself missing the webbed, scaled texture of Lea’s original form. “I’m considering myself fortunate that the merman who found me thought I wasn’t appetizing enough to eat.”

Lea tossed his head back and barked out a laugh at that, as sharp and bright as the sun itself. And when he met Isa’s eyes again, there was a heat behind them that sent a spike of warmth to the pit of Isa’s stomach. 

“Who said you were unappetizing?”

The rest of the day passed without comment, but later that night, Isa found himself pacing his room, unable to forget the way that Lea had stared at him— as if he was something to be savored. As if Isa was someone he wanted to please. 

The look had set an odd warmth in the pit of Isa’s stomach, and now he couldn’t get it out of his mind. He was about to call the night a loss, when suddenly there was a knock on his door. Carefully opening it, Isa blinked in surprise when he saw Lea there, holding a candle. Its dim light caught the mischievousness in Lea’s eyes in a way that was helplessly alluring. The simple robe that Isa had lent him was too large— slipping almost intentionally from his shoulders that allowed for a shameful glimpse of his collarbone and the barest hint of two, tanned buds on his chest. Isa felt caught, just as he did earlier in the gardens. 

“Well? Are we going to stand here all night? Or will you let me inside?” Lea purred in a voice that seemed perfectly suited for a predator. There was a pause. And then Isa grabbed Lea by the labels of his robe and yanked him inside. 

It was almost impossible to say who initiated the kiss, but both of them were lost as soon as their lips collided. Isa felt his heart pound in his chest as Lea slipped the robe from Isa’s shoulders, his motions fluid and gentle, as if they were still underwater. But more than that, Isa found himself consumed by Lea’s kiss, which was as fierce as the sea in a roiling storm. 

But questions still burned in Isa's mind, nearly as fierce as his desire. Despite all his actions, Lea had failed to share many aspects of their past— let alone how they had become separated. "Lea," he gasped, "Maybe we should talk first." 

"In the morning," Lea panted, fumbling for the knot tying Isa's robe together, "We can talk about it in the morning, I promise." 

Their lips crashed together again, and Isa could find no desire to argue. All he could do was clutch Lea, as their robes fell to the floor. 

There was a gentle push, and Isa released a muted gasp as his back hit the bed. Before he could move, he found Lea straddling him once more— green eyes practically glowing in the dim light. Had it only been that morning, when Lea had first emerged from the ocean and held him down, just like this? 

However, Isa was broken out of his thoughts as Lea reached between them, gently wrapping his long fingers around the half-hard flesh of Isa’s cock. Isa gasped, hips bucking into Lea’s touch. Immediately, Lea withdrew, a worried look creasing his eyebrows. 

“I hurt you,” he stated, regret lacing every word.

“No,” Isa said desperately, shaking his head. He reached slowly for Lea’s hand, as if afraid he would skitter away if he moved too quickly. “You didn’t hurt me. You just...” He swallowed thickly, feeling his cock throb in the open air. “You’re just good at this.”

Lea tilted his head, green eyes glinting deviously as he caught Isa’s meaning. “So you enjoyed it then?”

Isa felt his face catch fire at Lea’s sly smile. “I enjoyed it just fine,” he snapped, desperate to move past this point.

“Then there's no need to hold back.” And before Isa could prepare himself, Lea’s hand was suddenly on him once again, his cool hands exploring and tracing every inch of hardened flesh. He pushed Isa down, so that he reclined fully on the blanket rucked underneath him. Lea’s touch was far more intentional now, rather than merely curious. And every time Isa keened or shook, Lea’s eyes would flash at him, with a green tint that made him think of thick seaweed, entwining around him tighter and tighter until all he could do was give himself to their grasp. 

But even still, that did not prepare Isa for the tentative lick over the head of his cock. Isa snapped up by his torso, looking at Lea with wild, desirous eyes. Lea looked far more pleased than he should be. “I thought I remembered you liking that,” he said, long fingers idly playing with his length.

This man was going to be his death, Isa promptly decided. His chest rose and fell in great heaves as he watched Lea lean down and lap up the precum dripping from his cock. Gripping the sheets, Isa fell back with a low moan and drew his hand through Lea’s hair, streaks of red slipping between his fingers. He fought to keep his eyes open— to drink in this sight so that it stayed with him forever. Beyond this life and into the next. But what met Isa’s eyes nearly brought him to a sudden completion. 

At the crux of his thighs, Lea drew his tongue down the length of Isa’s cock, as if trying to memorize its shape with his tongue alone. It was tortuous to watch and even more so to experience, as Lea felt no pressure to rush this experience. Slowly, Lea began to take Isa’s head into his mouth, his lips stretching over the heated flesh of his cock. Isa could be spellbound by the sight alone, but Lea’s eyes— fuck, his _eyes_ — caught something in his heart. They blazed with a light that could survive the darkest depths. And even when Lea began to bob his head down Isa’s cock, they did not break their gaze. Was this how an animal felt, when they were caught as prey, Isa found himself wondering. Was that why his heart was pounding so loudly in his chest? 

Release came quickly for him, sparked by desire. His back arched and his heels skidded against the blankets as he gasped out Lea’s name. 

And Lea, from his position, simply smirked down at Isa, licking his lips with a deeply satisfied expression. “Now it’s my turn,” he murmured. And slowly, he rose and began to crawl up the bed to claim Isa’s lips in a searing kiss. 

And as the hours of the night turned to dawn, Isa found himself lost in Lea’s touch. Despite having no prior experience with humans, Lea’s touch was deft and practiced enough to test even Isa’s stamina. 

But even in their soft, sated moments, where their legs tangled together, Isa couldn’t imagine himself any more satisfied than he was at this moment. 

So when dawn gently rose through his windows, Isa found himself reaching for Lea’s side of the bed— only to find his space unoccupied but still warm. Knowing that meant that Lea wasn’t too far away, Isa drew on a pair of trousers and boots and went in search of his missing guest. 

A smile crossed his lips, as he guessed that Lea would most likely desire to be near the water. “Lea?” he called out, his boots sinking into the sand surrounding the lagoon. “Are you here?”

Seeing a shadow near an array the rocks that rose from shallow end of the water, Isa smiled in relief. “There you are. You know, you could have woken me up before you left.”

A dark, familiar chuckle came from the shadowed figure. “I’ll keep that in mind for next time, handsome.” Slowly, a familiar figure stepped out into the light, his toothy grin sharpening as he extended his arm, pressing the barrel of his pistol against Isa’s temple. “Gotta say though, it’s good to see that you weren’t turned into fish food. Although it looks like something else took a tasty bite out of you,” he smirked, eyeing the angry red marks that littered Isa’s throat. 

Suddenly, a dozen figures seemed to pull themselves from the shadows. An ambush, Isa belatedly realized. Reaching for the sword he usually kept strapped to his waist, Isa’s heart fell as he grasped only air. 

Seeing the aborted gesture, Xigbar clicked his tongue and gave Isa a sympathetic look. “Well, ain’t that just too bad.” 

In the space of a heartbeat, Xigbar cracked the butt of his pistol against Isa’s skull— sending him sprawling. “Hold him down,” he directed the men behind him, “but don’t hurt him yet. We need our bait alive if we want to fry this particular fish.”

“Bait?” Isa repeated, unsuccessfully trying to break arms free from the men’s tight grip. His world was spinning around him, and all he could feel was a growing sense of unease. 

“Yeah, bait. That’s you, if you’re still having trouble putting the pieces together,” Xigbar said, scouting his eye out for something unseen. “Since you’re here, I might as well spell the rest out. Did you ever wonder what we were looking for on that ship of yours?” 

Isa shook his head, a sharp ringing echoing in his head. “Treasure, I presumed. You’re pirates after all.”

“Half-correct, captain, I’ll give you that. But we were looking for some _one_ — not just some trinket. You, actually,” he shrugged. 

“Me?”

“Yeah, unbelievable, right? But here’s the thing,” Xigbar said as he continued to dart his eyes at every shadow— particularly those in the water. “You’ve been experiencing a lot of “unbelievable” shit lately. Haven’t ya?” Xigbar’s grin grew wider as Isa stiffened. “That’s what I thought. You see, I don’t know what you’ve heard, but there are many parties, who are interested in similar, “unbelievable” creatures. And whenever there are old geezers looking for knowledge, there are always going to be people like us, providing it to them at the highest cost.”

“So you do it for coin,” Isa said, “And now you want to use me to draw out your ‘target’? A disappointingly simple ambition and plan, I have to say.” 

Xigbar turned his face more towards Isa, and maybe it was the way that the early sun reflected across the water, but for a moment, Isa could have sworn that the man’s remaining eye glittered gold. 

“You really don’t remember anything, do you?” he purred, stalking towards Isa with a predator’s grace. “It was _your_ remains we were looking for, Captain. You know, back when you had a tail. 

“We were just supposed to catch the two little tykes that you two were dragging around. The younger fishfolk are, the stronger their magic, you see. But then you just _had_ to get in the way, defending the brats until your last breath. Or so we thought. Me and the gents left for a cart, and were about to carry your thrice-cursed body for the highest bidder.” A dark look passed over Xigbar’s face. “But then Ansem and his brood showed up. 

“That was a clever trick you pulled, you know. Playing dead like that, then turning into a human. That little ‘defense mechanism’ of yours got you a one-way trip into Ansem’s protection. The man even set you up, making a captain of you too. Meanwhile, your sea-damned boyfriend was out for blood in the ocean. Lucky for us though, losing you was just the kick in the tail he needed to become more powerful. All we needed to make our fortune was decent bait.

“So when we came across you on the ship, who better to throw overboard and lure out the fish that got away? The others didn’t know that you matched the description of what we were looking for, but hey,” he shrugged genially, “Why share the wealth, when patience yields its own rewards?”

Isa swallowed, his head spinning. Whether it was from the concussion or the revelations, he couldn't say. But as Xigbar's words whirled in his head, vague images slowly came back to him— blurry but still recognizable. More and more came, until Isa felt that his lungs would collapse under the weight of the flood. His head throbbed, but he could hardly care in that moment, as all of the images clicked together, creating one clear memory. One of swimming in crystal-clear waters and two small figures darting towards a coral reef, as he reached to brush his webbed fingers through a shock of unruly red hair. 

Roxas. Xion. _Lea._

Isa's breath caught. It was all true, he realized. Every word that Lea had told him. But unfortunately for Xigbar, he now remembered one more thing: a gleaming golden eye staring down at him, as his body was dragged onto the sand.

“How do you know all this?" he growled— the brigands' grip being the only thing keeping him from mauling Xigbar himself.

Xigbar gave a wicked smile, curling a finger around a blue forelock. He yanked Isa forward by his hair, close enough to hiss in his ear. “Well gee, it’s almost like I know enough about fish-folk to be one. And if I was, then who better to exploit the fat, lazy fish of the sea and turn a profit? And who knows? Maybe I’ll go back one day, with enough gold and harvested magic to create a little kingdom of my own?

Isa felt his stomach drop, but before he could say a word, one of the men cried out. 

“Boss, he’s here! He’s—”

A water geyser suddenly burst from the lagoon, rising at least a dozen feet above the hired muscle. 

“Xigbar!" a voice snarled out, "You won’t take him from me again!” Whipping his head over, Isa saw Lea standing in the sand, fangs drawing blood from his lips. 

Clouds of steam billowed from the geyser of water, as if controlled by an unseen force. And quick as a serpent’s strike, a tendril of water shot out, enveloping the nearest brigand’s face. The smell of seared flesh suddenly filled the air as the man screamed, desperately trying to escape the helmet of water fixed over his head. But Lea made a clenched gesture with his fist, and the man suddenly went limp. As the water shot out to encompass the heads of the other brigands, Isa saw that the man’s face had been boiled off entirely. The remaining flesh was scalded, raw, and red, and his fingers twitched uselessly in his final death throes. 

“Just our luck,” Xigbar spat out, “A goldfish that doesn't know when to go belly-up.” As another one of his men fell limp to the sand, steam rising from his faceless body, Xigbar propped up the corpse and used it as a shield to get himself out of the shallow waters of the lagoon. 

“Enjoy this little victory while it lasts,” Xigbar growled out, fangs poking out from his lips. “Just remember, chump like you is what draws in the sharks.”

With the crack of something louder than any pistol, Xigbar vanished from the beach, leaving the last of his men to writhe in agony on the sand. With their enemies either dead or retreating, Lea collapsed onto his knees. But before he could hit the ground, Isa caught him, holding him reverently. “You idiot…”

“Like I already said,” Lea smiled, pale but uninjured. “You have a knack of getting into trouble.”

Exasperation flickered across Isa’s expression, only to be immediately replaced by relief. He tightened his arms around Lea, who didn't waste a moment in returning the embrace. Their arms were iron bands around each other, and Isa nuzzled his face in the crook of Lea’s neck, drinking in the scent of salt. 

“I can’t stay like this forever, Is’,” Lea murmured, tucking a strand of blue hair behind his ear. “Xigbar will be back, and Roxas and Xion will need my help. I’ll have to return to the water soon. But… you have a choice to make.” 

Isa tilted his head up, meeting Lea’s eyes. Regret and sorrow echoed there, as if Lea was preparing himself to meet another tragedy. “You can come with me. Or... You could stay here as a human, with this life you've built for yourself.” 

“But what about you?” Isa asked, cupping Lea’s cheek. 

Lea gave a watery laugh. “Don’t you worry about me. I’ll be just fine.” Holding Isa’s gaze for a moment, he sighed and bent his head to press their foreheads together. “For a long time, I considered just taking you— damn the consequences. But then I saw the possibilities you could have here. Whatever happens next… it has to be your choice.”

Isa paused, not quite sure what to say. But to Lea, the silence already spoke volumes. His heart twisted deep in his chest, and he swallowed thickly. 

“Lea…”

“I don’t think I’ll be able to risk bringing Roxas and Xion here," Lea interrupted with a nervous laugh, "but they’ll want to give you trinkets at least. You know kids and their stupid shells.”

“Lea!” 

The red-haired man blinks and looked at Isa in surprise. But he stayed silent, waiting for Isa to speak.

Isa drew a deep breath. “I’m coming with you.”

Lea blinked. “Huh?”

Isa reached to weave his fingers with Lea’s. “I’m not staying here. I want to come home.”

Lea paused as a look of delight slowly brightened his face. Raising his hand, he began to rapidly rub his eyes. “Ugh, humans are so weird. Why do my eyes feel like they’re burning?” 

“Because you’re an idiot,” Isa replied, feeling tears begin to prick as well. Drawing Lea into a breathless kiss, Isa felt Lea press his hand against his chest, sharing his magic between them in a way that warmed Isa to his toes. Slowly, he felt a warmth locked away in his own chest become unwoven, spreading to his fingertips and toes. 

“Lea,” he murmured, “Let’s go home.” 

To any observers, they would have simply seen two men holding hands as they walked into the sea together. And as the sea foam lapped at their legs, their heads would disappear beneath the glittering waves. Two tails glinted in the light, one red and spiny while the other silver and sleek, with its fin curved like a crescent moon. In the distance, if one looked hard enough, they would see two heads— one red and one blue— meeting another pair of figures floating in the water. The last sign of them would echo as their voices briefly joined together in a song of reunion before the four figures finally dove underneath the water, back to their home in the fathoms below.

**Notes for the Chapter:**

> Please take a look at Michy's gorgeous artwork at her twitter[ here!](https://twitter.com/_yumiluna)  
> Please take a look at Lico's gorgeous artwork on her twitter [here](https://twitter.com/LicoriceRoll)!

**Author's Note:**

> Thank you guys for reading! Please give some love to [ Michy ](https://twitter.com/_yumiluna) and [ Lico](https://twitter.com/LicoriceRoll) for the art they created!


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